1. Field of the Invention
The invention disclosed herein relates to modulators of luminous energy typified by that generated in lasers, and particularly those modulators fabricated with oxide compounds which undergo transitions between metallic and non-metallic states in response to external stimuli.
2. Description of the Prior Art
Modulators of luminous energy radiating in the infrared, visible and ultraviolet spectra are, as a general premise, known by those skilled in the related arts. Likewise, lasers and means for their control are generally known. What is lacking is a laser system luminous energy modulator which can be inserted into the output path of a laser and operate as a reflective mirror or output coupler, translating between states at the behest of an external control with sufficient speed to generate pulsed laser outputs.
The related art known to the inventor appears in U.S. Pat. No. 3,455,627 granted to inventor Eugene C. Letter and U.S. Pat. No. 3,656,836 granted to joint inventors Baudoin de Cremoux and Pierre Leclerc. The teachings of the patent to Letter disclose an optical element which alternates between reflecting and absorbing states in response to the thermal effects of high energy density luminous radiation. The transition is a self-initiated thermal phenomenon, with the device reverting to its prior state upon the dissipation of the thermal energy added by the incident radiation.
The other patent, de Cremoux et al, also addresses the modulation of luminous energy. The device disclosed in this patent is defined to undergo transition between a first transmission state and a second absorption state upon the formation of an electric field within the semiconductor material constituting the device. Thereby, the modulation characteristics of this device are readily amenable to external control.
Neither of the foregoing disclosures describe a modulating device particularly suited to the job of extracting luminous energy from the resonating cavity of a laser. Notwithstanding the multiplicity of known techniques for accomplishing such an objective, none approach the simplicity or efficiency of a device which can be induced to undergo transitions between highly reflective and transmissive states.